Logic-based approaches for analyzing and evaluating arguments have been largely studied in recent years, yielding a variety of formal methods for argumentation-based reasoning. In this talk we introduce an abstract, proof theoretical approach to logical argumentation, where arguments are represented by sequents, conflicts between arguments are represented by sequent elimination rules, and deductions are made by dynamic proof systems extending standard sequent calculi. We show that this approach is useful for reasoning with different non-monotonic logics.